This invention relates to a fuel reforming apparatus for producing a carbon-monoxide free reformed fuel gas comprising hydrogen. More particularly, this invention relates to nonthermal plasma reactors for removing carbon monoxide from a reformed fuel gas produced from a fuel containing bonded atoms of hydrogen exiting a reformer. More particularly, this invention relates to nonthermal plasma reactors for reforming a fuel containing bonded atoms of hydrogen into a reformed fuel gas. This invention relates further to hydrogen-oxygen fuel cells, which comprise a fuel reformer for reforming a fuel into a reformed fuel gas comprising hydrogen, a carbon monoxide remover for removing carbon monoxide in the reformed fuel gas and supplying the reformed fuel gas to the fuel cell.
Hydrogen-oxygen fuel cells commonly used in spacecraft are now finding new applications such as fuel cell-powered electric cars, generator replacements, and local micro-power generation.
One of the most important technological processes is the production of hydrogen via a reformation process involving the reaction of water with, preferably, methanol. Alternatively, instead of methanol, other appropriate organic substances may be chosen to be reacted with water. Examples of such alternative organic substances comprise volatile low-molecular weight hydrocarbons (such as methane, ethane, etc.), other low-molecular weight alcohols (such as ethanol, n- or iso-propanol, as well as aldehydes, ketones (such as acetone) and the like as well as natural gas and gasoline. In addition, ammonia can be used as well. Among other applications, this process is used, for instance, in the development of fuel cells where hydrogen so produced serves as fuel.
The reformation process of hydrocarbon fuel produces a fuel cell feed stream containing hydrogen, and also such principle by-products as carbon dioxide and water. The process also produces certain amounts of carbon monoxide, which is harmful.
In a conventional autothermal reformer a hydrocarbon fuel is injected into a heated chamber along with water vapor and air. In the heated chamber the fuel is vaporized, to ensure high efficiency operation.
The hydrocarbon fuel burns by reacting with a small amount of air to yield carbon monoxide and hydrogen, as can be shown in case of methane as reaction (1):

In addition, the hydrocarbon fuel reacts with the water vapor also releasing hydrogen and producing carbon monoxide, for example, in case of a methane fuel as reaction (2):

The air allows combustion of a small fraction of the hydrocarbon fuel, elevating the temperature of the reactor and providing power to sustain the endothermic reforming reaction. The combustion is rich, so nitrogen oxides are not generated.
Carbon monoxide generated as a result of reactions (1) and (2) has an effect of poisoning the fuel cell at levels as low as 10 parts per million (ppm). Carbon monoxide is, therefore, a harmful by-product, which should be removed. In order to remove carbon monoxide and also in order to produce additional hydrogen, additional water vapor reacts with carbon monoxide to produce additional hydrogen and releasing carbon dioxide as a waste product as reaction (3):

However, it does not remove all carbon monoxide. The concentration of carbon monoxide remains still too high even after the gas stream exits the reactor. The removal of the remainder of carbon monoxide is achieved by either of two thermal processes, therefore in a water-gas shift reactor (WGS), or in a preferential oxidation reactor (PROX). The stream of hydrogen contains some carbon monoxide released as a result of reactions (1) and (2) which is then directed to a preferential oxidation reactor. The oxidation of CO occurs with the reaction (4):

The oxygen in reaction (4) is provided by admitting air. Requirements of CO-conversion reactors are very stringent. In particular, they must reliably reduce the concentration of carbon monoxide in the gas stream exiting the reformer from about 10% to less than 50 ppm. Otherwise, the fuel cell stack will be poisoned, leaving the vehicle inoperable and an exhaust harmful to the environment will be generated besides.
Hydrogen fuel purged of carbon monoxide as discussed above is directed to a fuel cell where it combines with air to produce electricity, water vapor and heat, heat being recycled to maintain the Partial Oxidation reactor at a proper temperature. The whole system can be used to propel a vehicle with practically no emissions other than CO2.
New applications are driven by the need to find alternatives to the internal combustion engine, and in the case of micro-power generation, the need to avoid building giant power-generating stations and high-voltage transmission lines. A key impediment to rapid adoption of fuel cells for these applications is the absence of an infrastructure for delivery of hydrogen, and of efficient, safe means to store it. Reformers answer this need by using an onboard chemical process to extract hydrogen from hydrogen-rich gases such as natural gas, methanol, gasoline, or ammonia.
The conventional autothermal reformers and CO-conversion reactors described above can be used to produce essentially CO-free hydrogen, they are however plagued by numerous problems and disadvantages. They are very complex, bulky, cumbersome and very expensive devices with long start-up latencies and short lifetimes. Especially for the automotive application (fuel cell powered vehicles), these characteristics are objectionable because they add bulk and weight to the car and require the driver to wait while the reactors come up to temperature before he can drive the vehicle. Therefor they require substantial warm-up time. In addition, their response to a change in the gas flow rate is too sluggish for automotive use. All these disadvantages are also typical even for systems not requiring the CO conversion reactors, systems using for example ammonia as a fuel and not producing carbon monoxide.
A second type of a conventional thermal-plasma reformer is also known, but this device has not found common application because of the huge input power, which is required. Most of the power input to the plasma ends up merely heating the gas, which is an inefficient use of electrical power.
“The Industrial Physicist, April 2000, page 14” discloses a thermal-plasma reactor which treats a small sidestream of gasoline vapor, and the resulting hydrogen-rich gas is added to the gasoline-air mixture being injected into the internal-combustion engine, thereby increasing its efficiency and reducing its pollution. Yet this system does not provide a zero-emission vehicle and is a mere modification of an internal combustion engine.
In view of the foregoing there are problems and disadvantages inherent in reformers and CO-conversion reactors. Such reformer and CO-converter should preferably be simple in design, lightweight, compact and inexpensive. It should be able to ensure efficient delivery of hydrogen-containing fuel to a fuel cell and to avoid formation of harmful carbon monoxide. It should be able to be started instantaneously and to respond to the change in the gas flow rate immediately.
There exists no known prior art describing a reformer and CO-converter having all the advantages and benefits described above. Yet the need for such is acute.